YINGXIU, China — Rescuers rushed to reach 24 coal miners trapped underground by China's earthquake almost two weeks ago, officials said Saturday as the government sharply raised the death toll and warned it could exceed 80,000.

It was not known if the miners were alive, but authorities were hoping for the best until they learned otherwise, said Wang Dexue, the deputy chief of the government's work safety department.

"We have had the miracle in the past that a miner was found alive after being trapped underground for 21 days," Wang told a news conference in Beijing. "We are carrying out rescue work on the assumption that they are still alive. We absolutely will not give up."

The 24 miners were trapped in three mines in Sichuan province, Wang said, without giving further details. Sichuan bore the worst of the May 12 quake — China's biggest disaster in three decades.

China's mines are the world's deadliest, with explosions, cave-ins and floods killing nearly 3,800 people last year.

Toll risesPremier Wen Jiabao returned to the quake zone on Saturday and hosted U.N. Secretary-General Ban Ki-moon in a visit to Yingxiu, one of the hardest-hit towns. Jiabao said China's death toll has passed 60,000 and could rise to 80,000 or more.

Wen's estimate Saturday was a sharp increase over the 55,000 deaths reported earlier by the government.

Wen made the comment as he and United Nations Secretary-General Ban Ki-moon visited Yingxiu, a town near the epicenter of the May 12 quake.

Wen said fatalities "may further climb to a level of 70,000, 80,000 or more."

Ban arrived to visit earthquake relief efforts as experts searched for 15 radiation sources buried in the rubble and survivors moved out of possible danger areas downstream from rivers dammed by landslides.

Ban flew to Yingxiu, about 40 miles southeast of the May 12 quake's epicenter in Sichuan province and went into a meeting with Premier Wen Jiabao, who also was visiting the area.

Ban's visit was meant to "express his care for those who suffered" in the quake that killed more than 55,000 people, the government's Xinhua News Agency reported.

As relief workers grappled with finding tents and getting food and medical care for the displaced Friday, rescue teams evacuated survivors living downstream from rivers dammed by landslides. With their waters pooling, the blocked rivers could breach the earthen barriers, a danger that would grow with coming rains or in aftershocks from the quake that led to 55,000 deaths.

Radiation 'sources'
Meanwhile, the Environmental Protection Ministry said experts from its National Nuclear Safety Administration were trying to contain 15 unspecified "sources" of radiation.

Some 50 potential radiation sources had been buried by the quake, Environment Vice Minister Wu Xiaoqing said Friday in Beijing. Although 35 have been secured, 15 remained buried under buildings and houses and despite being located were inaccessible, he said.

Wu said the radiation was not leaking. But the number of unsecured sources was far higher than the two the agency reported earlier this week. China has said all nuclear facilities were safe — an assurance Wu repeated — and foreign experts have said the unsecured sources were likely materials used by hospitals and factories or for research.

The search for radiation sources and the evacuation of flood-threatened communities showed how precarious the situation remained nearly two weeks after the quake. The confirmed death toll rose again Friday to 55,740 and another 24,960 were missing, the Cabinet said.

Shifting focusEven as it battled to bring relief to the devastated areas of Sichuan, the government was shifting focus to long-term reconstruction and away from the search for survivors and bodies among the wreckage.

Vice Governor Li Chengyun said the province would aim to rebuild roads and cities within three years. Beijing also ordered its richest provinces and cities to adopt areas that were hit hard by the quake and to start sending aid right away, especially tents and drinking water.

Tents were in great demand in the town. Signs urged people to pay attention to hygiene to prevent disease outbreaks. Red banners hung across the main street said, "There is no difficulty that the heroic Chinese people cannot defeat."

As many as 9,000 injured will be transported to other provinces, Sichuan Vice Governor Li said, as the large casualty toll has overwhelmed local hospitals in the province. He said more psychologists were needed to help survivors cope, especially children orphaned by the quake along with students who saw many classmates killed in collapsed schools.

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